We waited and, in one sense, wasted decades, scientifically establishing carbon emissions, and their effects. Now its about sequestration, on and in the ground: a different issue, yet the same

Science told us the risks of climate change. We needed it, to explain how nature works, in a way that no one can observe.

Now, it joins the race for good solutions. Where the science is disputed, as it is on soil carbon, is there time left to explain everything, paper by paper, and peer-review? And yet, there’s no time, either, to waste on crackpot theories.

On soil carbon, there seems a gulf, between what science can validate at this point, and observations on the ground, dismissed as ‘anecdotal’, but racing to establish themselves in terms that are scientifically, agriculturally, economically credible.

I don’t know who or what to believe. The anecdotes are compelling; I'm not equipped to dispute the science. And — since this seems a fractious, rumbly area — I will say from the outset that what follows is over-simplified, but I hope, without being simplistic.

It contrasts Dr Christine Jones’ findings with those of our own Jacqueline Rowarth, professor and Massey director of agriculture. It 'contrasts' them, although both Jones and Rowarth are doing the science of pastoral agriculture: this is not a simple dichotomy between one woman who showed us some nice paintings and goes out to dig in the paddock, and another with some scary graph-and-flowchart thingies. And yes, one is Kiwi, one Australian — countries with such different soil circumstances, they might inhabit different planets, making contrasts or comparisons spurious.

Jones says the Kyoto Protocol, which New Zealand hasn’t signed for soil carbon, measures the wrong thing. It applies to the top 30 cm. The most significant carbon changes, she says, happen at depth, from 40-100 cm.

Whether or not for the right reasons, then, New Zealand officials’ instinct and advice not to buy into it, on the basis that we don’t know enough about how this all works, may have been the right one. And their judgement is backed by Rowarth, too. Scientific unanimity on this, then, phew.

Jones paints a verbal picture, and shows her audience actual painted pictures, of what Australian pasture used to look like, two centuries ago when the settlers arrived: deep top soil and lush native grasses mid-summer, truly, the lucky gorgeous country. It eroded, she says, through land mismanagement, to the dust bowl we know today. Downstream, it kills rivers, from silt washing into them, and people too, perhaps: depleted Aussie soil grows depleted food.

If Australia has a lesson for New Zealand, she says, it would be: don’t copy us.

She shows us a former family farm, now split into four, among four brothers: a natural case study. One of the brothers manages his soil biologically. He re-sowed native perennial pasture grasses, and keeps the soil always covered, by ‘pasture cropping’; when he sows winter cover crops, for example, they’re drilled straight into the grass. He manages overgrazing, yet his land now supports double the number of stock of his brother’s, on the neighbouring property.

And the two places look quite different, visually, and on the hard data. Spadefuls, side by side, show different soil structures, with more topsoil on the biologically-managed property. And different soil carbon levels: up to three times more in the top layers, to 30 cm, and a PhD (“I can’t release the data, unfortunately”) in the pipeline that will show big positive changes, at 40-100 cm depth.

These are farmers managing without conventional fertiliser, using only natural applications: vermiliquid, and compost tea. Building carbon, Jones says, builds nitrogen and potassium, without external inputs.

Most importantly, though, it’s the grasses doing the work. She shows us a Western Australian desert, in five-month 40-degree summer drought. A pitiful little cover crop of grasses seems to condition the soil: it’s visible in the soil itself, and the performance of intersown crops, that perform best right on top of the stunted grass rows.

She thinks it is their roots, doing deep carbon storage. Photos of the roots of the perennial grasses, compared to annual and urea-fertilised grasses, show healthy-enough looking tops, of comparable size, but hardly any roots at all on the fertilised sample, and fewer roots on the annuals, compared to the great bearded perennial structures.

CSIRO, Australia’s national science agency, calls this all ‘anecdotal’. But it will, she says, be published and peer reviewed in short order: it will be real science, in other words.

Since Jones works on highly depleted Aussie soils, unlike New Zealand soils, it’s perhaps worth noting that another New Zealand speaker, Plant and Food Research’s Markus Duerer, presents on the results of a comparative Kiwi study — literally, on a couple of kiwifruit orchards — with similar conclusions, about carbon storage at depth, and deep root growth as the most promising method of soil carbon sequestration.

Massey’s Jacqueline Rowarth, on the other hand, tells at length how she, and her students and colleagues, have struggled to validate this science. It’s such an uncertain science, she concludes, that it isn’t feasible to count on soil-stored carbon as a feature of an emissions trading scheme, or for international carbon accounting, at this stage. It would be a risk for farmers; it could result in them being penalised.

Hers was a story about dead plants, and wildly variable results, out in the field.

She hasn’t abandoned the cause though: on the contrary, she wants to see more research, and better-funded research. Impecuniosity, and the inadequacy of Agresearch’s present funding grant, was a refrain of her talk.

Rowarth is a scientist with enormous stock in the farming community, as someone who understands farmers’ issues and champions their cause. She has said publicly that agriculture needs excellent science; they are a natural partnership.

Her views count. Dubbed the “inspirational” Jacqueline Rowarth by Federated Farmers, she was their ‘agricultural personality of the year’ in 2009. She told Rebecca McFie recently that farmers should be paid, to introduce good, environmentally-friendly technologies — subsidised, in other words, as they are in Europe. She challenges organics’ productivity, and says intensification is our opportunity, given the world’s scarce arable land.

She and Christine Jones are doing their science in quite different circumstances. But a question in my mind, as I listened to them both, was whether there’s a different mindset at work here too: a factor that surely even a scientist must take into account, in assessing the validity of the results, and finding out what works.

I wanted to know what, in practice, Rowarth isn’t doing that Jones is, and vice versa.

If something is observed in the field, and a scientist can’t validate it, or can’t validate it quickly enough, does it mean it isn’t true? I try things in my garden, and keep doing what my eyes tell me is working, and will give me a firmer foothold on this planet; I don’t always need to know why or how.

But that’s not how the international Kyoto accounting system works, of course, or science, or the many vested, and cynical, interests. And that makes me fear for us all, knowing how long it took, to establish climate change, and that we don’t have the same time left to find and implement its solutions.

Comments (6)

by Peter Donovan on September 18, 2010
Peter Donovan

Thanks for the thoughtful observations Claire. Though I don't have firsthand knowledge of the work of either Jones or Rowarth, one of the tricky parts of the soil carbon opportunity or issue is that it's mainly a people issue or opportunity, though there are technical aspects.

Working with positive deviants who somehow have figured out how to increase soil carbon is quite different than working with what are often called "best management practices," perhaps implemented in a routine or offhand way. Scientists who work with the latter will probably be unable to "validate" the results of those who work with the positive deviants.

Most scientists, through habit and training, seek the one best "practice" for sequestering soil carbon, and treat it as a convergent problem. The positive deviants are troublesome, as they cast doubt on the models.

Soil carbon isn't a technical problem, it's a social issue of beliefs and behaviors. Probably a divergent problem or opportunity.

If we want to find out how fast a human can run 100 meters, do we build a computer model, do a literature search, or ask a panel of experts on human physiology for a prediction?

No, we run a race, or more than one. This is the idea behind the Soil Carbon Challenge, which uses practical monitoring of soil carbon change to find and recognize positive deviants.

Who are the best leaders for a movement? Those who aren't sure the goal can be accomplished, or those who have had some measure of success?

Thanks for reading.


by Claire Browning on September 20, 2010
Claire Browning

Thanks Peter. All the way from the US of A!

I did read your site. Thank you for linking to it, and I wish you the best with your project. A very small New Zealand land management system, otherwise known as 'my garden' is at your disposal, if you want it ... 

Extracts, for others who may be interested:

... it is tempting to see the building of soil organic matter as a single, broad, high-leverage strategy for taking responsibility for the biosphere’s carbon cycle, and addressing climate change along with other problems. Soils, depleted as many of them are, contain far more carbon than the atmosphere and forests combined. The flow of carbon in and out of soils is about 8 times as large as what are usually considered anthropogenic emissions (fossil fuel burning and deforestation). A wide variety of human activities--agriculture, grazing, biomass burning, forestry, or protection from other uses—greatly influence these flows, often in surprising directions. Atmospheric carbon can be turned into carbon-rich soil organic matter using solar energy (self-reproducing plants), without the need for expensive collection and concentration systems. Even the poorest people can do it. And organic matter greatly increases the fertility and water-holding capacity of soils, thus addressing the root of most of the major issues or problems facing humans now.

[But] ... It's hard to imagine current policy systems implementing a broad-scale enhancement of soil organic matter. No large organized political or economic power bloc stands to benefit directly from it, or makes these underground benefits recognizable to the larger public. It doesn't visibly align with the flagship issues of the environmental movement such as species conservation, wilderness protection, or pollution. Within the framing of climate change as pollution, soil carbon is suspect because it is viewed as an offset or excuse for fossil fuel emissions, which brings concerns about permanence, additionality, and verifiability. Increasing soil organic matter is crosswise to the agendas of agricultural modernization, whose defenders regularly dismiss it as insignificant, unpredictable, and too hard to measure.


With the problem increasingly institutionalized as one of atmospheric pollution, and with the power for change assigned to technology or to limits on it, and with steady and committed resistance to this framing, we aren't in a position to solve it. Clean energy systems and emissions reductions, while necessary and beneficial, are not enough. We are trying to extend technology with atmospheric dialysis, air capture of carbon with lye, and even with fantasies of reversing the basic chemistry and thermodynamics of coal combustion. We still cannot seem to imagine or recognize the hen that could unscramble the planetary egg.

But she may be quietly edging into the picture.

The biosphere is the sum of all the living and the dead. It doesn't just sit there looking pretty, wild, or vulnerable. It does work, a lot of it. ...

Bare, uncovered soil indicates not only leakage of soil carbon into the atmosphere, but the absence of life that can replenish it. Since before the dawn of history, human habits and activities have contributed to the oxidation side of the biosphere's carbon cycle and subtracted from the photosynthesis side. Over the vast areas of bare soils between the plants on much of our grasslands and croplands, the biosphere and its carbon cycle—the solar-powered engine of all ecosystem services—is barely idling.

These are still unfamiliar concepts and phenomena. Compared to our noisy and concentrated energy technology, carbon cycling is quiet, gradual, spread out over vast areas, and usually invisible. It doesn't have any corporate or institutional sponsors. Yet on land alone, even with many cylinders out of play, it does 10 times the work.

... Though there is a huge diversity of practices, one common denominator is to let solar-powered plants, animals, and microbes do more and more of the work, and to keep soils covered with live or dead plants throughout the year. ...

These reversals challenge widely held beliefs that biological processes are slow and weak, and that only technology (or geologic cataclysms) can change landscapes rapidly. But they also suggest a hypothesis. What if, by managing the soil surface so as to reduce losses of soil carbon and increase the gains, we could gain enough leverage over the carbon cycle to unscramble the egg?

... The biosphere's carbon cycle operates through self-motivated, self-reproducing organisms, most of them microscopic or vegetative. It cannot be forced. It's process, not just events, and complex relationships, not just mechanical practices. How do we work with the biosphere's carbon cycle, and let it do its best work? What kind of person, what kind of behaviors are likely to succeed at this, in varied situations and environments? We don't know. Policy, regulation, or best practices as determined by research aren't good strategies for exploring the possibilities.

The original draft of the post had a few extra paras in it, about why I think soil carbon has and will continue to struggle. In the end, I thought they rambled too far off track, and took them out. You've said it for me, in the borrowed bits above, so thanks, again.

by Sean on September 22, 2010

To answer your question as to why the NZ government policy makers are very cold on soil carbon accounting you have to go back to the early 90's when all this stuff was just starting to be noticed by many in NZ. The debate in the treasury etc. then was how the greenhouse/Kyoto changes would effect government finances. Trees and forestry sequestration was seen to be easy to manage, only a few large main players and the crown the biggest owner of forestry land in the country. Soil carbon sequestration on any scale was seen to require major changes of operational methods by tens of thousands of individual farmers. The only way this could happen is if the farmers themselves kept essentially all the financial benefits. As you can imagine from that time the view of all parts of government has been that carbon sequestration in trees is great and that they would rather run around naked in a hailstorm than see soil sequestration play any part in NZ's carbon storage plans. I suspect that many in government no longer know why this is the view, they have just soaked it up from the culture. I will give you a couple of numbers to hint at the scale of loss that this particular example of greed has caused NZ. Back in the mid nineties when there was still some hope that NZ would have sane greenhouse policies my family ran a 5 year intensive carbon sequestration trial on some fairly ordinary poor pasture land. This was a tree/legume based system but the real eye opener was how fast soil was formed from the mulched debris. Some of the plot added over 100mm of black organic soil in five years. The bottom line is that this trial sequestered over 50 tons of carbon per hectare per year over the five years and the rate was accelerating towards the end. Multiply that number by the hectares of pasture in NZ and see what that gives you!! An added bonus was that this plot seemed to be an much more active methane sink than normal pasture. The drawback is that this very intensive management is expensive and labour intensive. Even sequestering at such a high rate it would not be economic below $25 a tonne for carbon credits. I suspect that someone in the wetter parts of the north island could win the soil carbon coalition challenge above. Other than that soil carbon sequestration, other than as a side effect, in NZ is a lost cause. There is no way that the government would let landowners keep enough of the gain to make it viable.

by Claire Browning on September 23, 2010
Claire Browning

Thanks Sean.

by Peter Donovan on September 24, 2010
Peter Donovan

Sean, I would very much like to hear more about your tree/legume experiment. In addition to the Challenge we are also keen on putting measured instances of soil carbon change on the map:


Again, to show what is possible, based on measurements, recognizing that not all measurements are equally repeatable.

Please contact me at info at soilcarboncoalition dot org


Peter Donovan

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